Insertion of carbodiimide into the Ln-N σ-bond of organolanthanide complexes.: Synthesis and characterization of organolanthanide guanidinates (C5H5)2Ln[iPrN C(NiPr2) NiPr] (Ln = Yb, Dy, Gd)

The synthesis and structures of three new lanthanide complexes incorporating tetra-substituted guanidinate ligand [(PrN)-Pr-i-C((NPr2)-Pr-i)-(NPr)-Pr-i] are described. Treatment of Cp(2)LnN(i)Pr(2)(-THF) (Ln = Yb, Dy, Gd) with N,N'-di-isopropyl-carbodiimide results in mono-insertion of carbodiimide into the Ln-N sigma-bond to yield Cp(2)Ln[(PrN)-Pr-i-C((NPr2)-Pr-i)-(NPr)-Pr-i] (Ln=Yb(1), Dy(2), Gd(3)), providing an efficient method for the synthesis of organolanthanide guanidinate complexes. It was found that an excess of N,N'-diisopropyl-carbodiimide did not affect the nature of the final product. Complexes 1-3 were characterized by elemental analysis, IR and mass spectroscopies. Complexes I and 2 were determined by the X-ray single crystal diffraction analysis. (C) 2003 Elsevier Science B.V. All rights reserved.